Singulation process, also known as dicing, is generally performed to separate a plurality of chips formed on a wafer. Various singulation techniques may be used to separate the plurality of chips formed on the wafer into individual chips for packaging. One of the common techniques used is mechanical sawing. In a mechanical sawing process, a diamond saw rotating at high speed cuts the wafer along saw streets or dicing channels to separate the chips from each other. However, crack or chipping tends to occur in each chip due to mechanical stress caused by the blade. Furthermore, it is very time consuming when mechanical sawing process is used to separate the chips from the entire wafer.
In an effort to mitigate the problems above, a plasma etch process has been proposed to be used in singulating or dicing a wafer. However, we have observed that conventional plasma etch process may not effectively separate the dies from the wafer and the singulated dies may also suffer contamination caused by the plasma etch process. Conventional plasma etch process may also result in rough or uneven lateral surfaces or sidewalls of the singulated die.
In view of the foregoing, there is a desire to provide reliable, simplified, efficient and cost effective methods for singulating semiconductor chips or dies from a wafer.